The present invention relates to a portable communication terminal which is capable of communicating with an information terminal, in particular to a method of converting a control protocol of the portable communication terminal between different kinds of networks.
Conventionally, an AT (Attention) command system is used in controlling data communication during data communication, and the like between a portable communication terminal and an information terminal capable of communicating with the portable communication terminal. In the AT command system, a control command and a data array are time-divisionally transferred in the same interface. A wireless WAN (Wide Area Network) CDMA (Carrier Division Multiple Access) communication section is formed in the portable communication terminal. The wireless WAN CDMA communication section carries out transmission and reception of communication data in a wireless WAN service area.
A wireless WAN data communication control block is connected to the wireless WAN CDMA communication section through a data interface. The wireless WAN data communication control block controls a communication in the wireless WAN CDMA communication section. The wireless WAN data communication control block receives a reception data from the wireless WAN CDMA communication section and sends a transmission data to the wireless WAN CDMA communication section. A command/data separation block is connected to the wireless WAN data communication control block through an interface and another interface. The command/data separation block separates a control command and a data array both transferred in the AT command system from each other. Between the command/data separation block and the wireless WAN data communication control block, a transfer of transmission and reception data is carried out through the interface while a transfer of a control command is carried out through the interface.
A portable communication apparatus external interface block is connected to the command/data separation block through a command data interface. Between the portable communication apparatus external interface block and the command/data separation block, a transfer of the control command and the data array both in the AT command system from the information terminal is carried out through a data interface.
In the interim, in the above-mentioned portable communication terminal, only one command data interface exists between the portable communication apparatus external interface block and the command/data separation block. As a result, the information terminal cannot send a control command to the portable communication terminal during data communication.
It is therefore necessary that the information terminal always monitors whether or not the portable communication terminal is during the data communication and so cannot receive the control command. Further, when the information terminal sends the control command, the information terminal must send the control command after enabling the portable communication terminal to receive the control command by the use of an especial sequence. Moreover, when necessary, the information terminal must turn the portable communication terminal to be capable of the data communication again after finishing the sending of the control command.
On the other hand, for example, a protocol called NDIS (Network Driver Interface Specification) is used for a control command in general LAN (Local Area Network) equipment. It is thereby possible to send the control command, even though the general LAN equipment is during data communication.
Under the circumstances, let the above-mentioned portable communication terminal be supplied not only with a data transmission and reception function by a wireless WAN but also with a data transmission and reception function by a wireless LAN. Accordingly, a method of controlling command/data communication in a case the wireless WAN is effective is different from a method of controlling command/data communication in a case the wireless LAN is effective. As a result, the conventional portable communication terminal has a problem that a method of controlling the portable communication terminal for the data communication becomes complicated.
Further, in the wireless WAN communication, the control command cannot be issued during data communication. As a result, an operation of the information terminal in a case of effective wireless LAN becomes different from that in a case of effective wireless WAN. It is therefore feared that a user of the information terminal comes to be confused.
On the other hand, if the control commands for the portable communication terminal in the wireless WAN is restricted to the NDIS protocol, it is feared that conventional application software installed in the information terminal become inoperable. Moreover, in a development of the portable communication terminal itself, a period for the development thereof is extended, since the conventional wireless WAN data communication control block is unable to be used.